Conception Calculator
Estimate a likely conception date from an estimated due date or last menstrual period.
| Pregnancy Dating Details | Enter Value |
|---|---|
| Calculation Method | |
| Date |
How to Use the Conception Calculator
Choose whether you know the estimated due date or the first day of the last menstrual period, then enter that date to estimate conception timing.
Practical Example
If an estimated due date is known, the calculator counts back about 266 days to estimate conception. From a last menstrual period, it estimates conception roughly 14 days later.
Factors That Affect the Result
Ovulation timing, cycle length and clinical dating differences can shift the estimate. Ultrasound dating and medical assessment may provide a more appropriate pregnancy timeline.
Related Tools
Ovulation Calculator · Due Date Calculator · Pregnancy Week Calculator · Date Add or Subtract Calculator · Days Between Dates Calculator
Frequently Asked Questions
Can conception date be known exactly?
Usually not from calendar dates alone; the result is an estimate.
Why count back 266 days from a due date?
That approximates 38 weeks from conception to the estimated due date.
Can cycle length change the estimate?
Yes. Earlier or later ovulation can shift the likely conception date.